Non-circular contact lenses with payloads

ABSTRACT

An eye-mounted display includes a scleral contact lens with one or more femtoprojectors that project images onto the user&#39;s retina. The scleral contact lens has a non-circular perimeter, for example elongated along the direction of the eye opening. The non-circular shape can result in less slippage and/or rotation of the contact lens relative to the eye. If the contact lens is elongated (compared to traditional circular lenses), then it can contain conductive coils that enclose a larger area. Thus, the lens increases coupling efficiency for power or data transfer. There can also be more space within the contact lens for payloads.

BACKGROUND 1. Technical Field

This disclosure relates generally to contact lenses with payloads,including for example eye-mounted displays.

2. Description of Related Art

An eye-mounted display has been proposed by Deering. See, e.g. U.S. Pat.No. 8,786,675, “Systems using eye mounted displays.” One type ofeye-mounted display is based on a tiny projector mounted inside acontact lens. The projector projects images onto the retina of a personwearing the contact lens. The projector must be very small to fit in thecontact lens, so small that Deering called it a “femtoprojector.” Atypical femtoprojector preferably is no larger than about one or twomillimeters in any dimension.

Each femtoprojector in an eye-mounted display includes an image sourceand an optical system. A femtoprojector's optical system is designed toproject images from the image source onto the retina so that the imagesappear in a person's field of vision. The femtoprojector optical systemsare constrained to fit inside a contact lens while also providingappropriate magnification and sufficient image quality.

Eye-mounted displays can be used for virtual reality applications andalso for augmented reality applications. In virtual realityapplications, the images projected by the eye-mounted display replacewhat the user would normally see as his external environment. Inaugmented reality applications, the images projected by the eye-mounteddisplay augment what the user would normally see as his externalenvironment, for example they may appear as additions to the externalenvironment. In both cases, it is usually important to project theimages onto the user's retina with fairly high positional accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure have other advantages and features whichwill be more readily apparent from the following detailed descriptionand the appended claims, when taken in conjunction with the examples inthe accompanying drawings, in which:

FIG. 1A shows a user wearing an eye-mounted display in communicationwith an auxiliary necklace.

FIG. 1B shows a magnified view of the eye-mounted display mounted on theuser's eye.

FIG. 2A shows a cross sectional view of an eye-mounted displaycontaining multiple femtoprojectors in a contact lens.

FIG. 2B shows a front view of an eye-mounted display containing multiplefemtoprojectors in a contact lens.

FIG. 3 shows another eye-mounted display mounted on the user's eye.

FIGS. 4A and 4B show oval and irregular perimeters of contact lenses,respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The figures and the following description relate to preferredembodiments by way of illustration only. It should be noted that fromthe following discussion, alternative embodiments of the structures andmethods disclosed herein will be readily recognized as viablealternatives that may be employed without departing from the principlesof what is claimed.

Contact lens devices that perform functions beyond just fixed visioncorrection may carry payloads in the contact lens, including electronicpayloads. For example, an eye-mounted display may be based on a contactlens that contains one or more femtoprojectors and correspondingelectronics. These displays project images onto the user's retina, whichcan provide an augmented reality and/or virtual reality to the user.There are many design challenges for such a device. For example, it isdesirable to reduce or eliminate movement of the contact lens relativeto the eye. If the contact lens slips or rotates on the eye, then theposition of femtoprojector(s) in the contact lens will change relativeto the retina. Mechanisms to compensate for this movement can make theoverall system unnecessarily complex. Other challenges includeefficiently transferring power and data to the contact lens andproviding enough space within the contact lens for the electronic andother payload components.

In one approach, a scleral contact lens with a non-circular perimeter isused. A scleral contact lens rests on the sclera (i.e., the white part)of a user's eye. Elongating the scleral contact lens along the directionof the eye opening can result in a better fit between the contact lensand the eye. The elongated shape of the contact lens increases the areaof contact between the contact lens and the user's sclera, thus reducingslippage and/or rotation of the contact lens relative to the eye. Theinterior surface of the scleral contact lens (i.e., the part contactingthe sclera) can also be customized to match the contour of the user'seye, thus allowing a better fit between the contact lens and the user'ssclera and further reducing contact lens movement relative to the eye.The non-circular shape also results in a larger perimeter, which can beused to accommodate conductive coils with a larger area, thus increasingcoupling efficiency for power or data transfer. The non-circular lenscan also provide more space within the contact lens for payloads.

In more detail, FIG. 1A shows a user wearing an eye-mounted display 100in communication with a necklace 160. FIG. 1B shows a magnified view ofthe user's eye and eye-mounted display 100. The eye-mounted display 100includes a contact lens 110. The following examples use a scleralcontact lens but the contact lens does not have to be scleral. Thecontact lens 110 has a non-circular perimeter 112 and extends below theupper and lower eyelids. In this example, the contact lens 110 has an“oval” perimeter 112 that is elongated along the direction of the eyeopening. Due to the curvature of the eye, the actual shape of theperimeter is three-dimensional. However, for convenience, it will bereferred to as oval if the two-dimensional projection onto a plane isoval. Due to the size of the contact lens 110, it is partially coveredby the user's eyelids.

The contact lens 110 also contains multiple femtoprojectors 120, eachrepresented by a white circle in FIG. 1B. The femtoprojectors 120project images onto the user's retina. The contact lens 110 moves withthe user's eye 100 as the user's eye rotates in its socket. Because thefemtoprojectors 120 are mounted in the contact lens 110, they also movewith the user's eye. Some femtoprojector(s) may always project images tothe fovea, and other femtoprojector(s) may always project images to moreperipheral regions which have lower resolutions.

In this example, the contact lens 110 also contains electronics 140 anda conductive coil 145. The coil 145 may be used to wirelessly transmitand/or receive power and/or data, for example via induction. To increasecoupling to the coil 145, it is desirable to increase the area enclosedby the coil. In this example, because the contact lens 110 is elongated,the conductive coil 145 has a larger area than would be the case for aconventional contact lens with a circular perimeter. To increase thearea enclosed by the coil 145, the coil may be located near theperimeter 112 and have a similar shape as the perimeter 112, as shown inFIG. 1B. For example, the conductive coil 145 may be constructed so thatit lies parallel to and within 0.3 mm to 3 mm of the perimeter 112(e.g., the coil 145 lies within 2 mm of the perimeter 112).

In other embodiments, the contact lens 110 includes a battery thatsupplies power to the femtoprojectors 120. The electronics 140 may beused to control the femtoprojectors, receive or process images from thefemtoprojectors, provide power to the femtoprojectors, and/or transmitdata to/from the femtoprojectors. The contact lens 110 may also includeother components.

FIG. 1A shows an implementation where, in addition to the eye-mounteddisplay 100, the user is also wearing a necklace 160 that containscomponents of the eye-mounted display system. In this example, thenecklace 160 includes a wireless transmitter 170 that transmits imagedata and/or power to the eye-mounted display 100. For an eye-mounteddisplay, reducing the data transmission rate is desirable, both becausethe available bandwidth is limited and because it is desirable to reducethe complexity and power consumption of electronics in the contact lens.

FIG. 2A shows a cross sectional view of an eye-mounted displaycontaining femtoprojectors 210 in a scleral contact lens 110. FIG. 2Bshows a top view, i.e., a view looking at the user's eye. In thisexample, there are three types of femtoprojectors 210A, 210B, and 210C,which have different optical designs depending on the desired resolutionand magnification. The retinal receptive fields are more densely packedtowards the fovea and become progressively less densely packed away fromthe fovea. Accordingly, in one implementation, femtoprojectors thatproject to the fovea generate higher resolution images on the retina,and those that project to the periphery of the retina generatecorrespondingly lower resolution images.

The contact lens 110 is separated from the cornea 274 of the user's eye270 by a tear layer 272. Over the cornea 274, the tear layer 272 may beas thick as a hundred microns or more while it may be only a few micronsthick over the sclera 282. The aqueous of the eyeball is located betweenthe cornea 274 and the crystalline lens 276 of the eye. The vitreousfills most of the eyeball including the volume between the crystallinelens 276 and the retina 278. The iris 284 limits the aperture of theeye.

The contact lens 110 preferably has a thickness that is less than 2 mm,and the femtoprojectors 210 each preferably fits in a 2 mm by 2 mm by 2mm volume, or less. The contact lens 110 should be comfortable to wearand maintains eye health by permitting oxygen to reach the cornea 274.In some designs, the optical paths from the image sources in thefemtoprojectors 210 to the retina 278 do not include any air gaps,although that is not required.

In FIG. 2B, the contact lens 110 is roughly divided by the dashed circleinto an optical zone 252 and a non-optical zone 254. Components in theoptical zone 252 may be in the optical path of the eye, depending on howfar open the pupil is. Components in the non-optical zone 254 falloutside the aperture of the eye. In addition to the femtoprojectors 210,the contact lens may also contain other components for datatransmission, power, and/or positioning. Data transmission componentsmay include antennae or optical/infrared photodetectors, data storageand buffering, controls, and on-lens processing. Power components mayinclude coils for power transmission and batteries for power storage.Positioning components may include accelerometers, gyroscopes, or otherstructures used for eye tracking and head tracking.

The use of a larger contact lens 110 can create more space 230 forcomponents in the contact lens. In addition, the contact lens and itscomponents can be colored to make them less visible to outsideobservers. For example, components that are positioned in front of theiris 284 can be made opaque with a color that matches the user's eye.Components that are in front of the sclera 282 may be given a whiteappearance or otherwise match the sclera. This allows components and thecontact lens 100 to be less visible.

In addition to the eye-mounted display, the overall system may alsoinclude a head tracker, eye tracker, and scaler. The system receivesinput images (including possibly video), which are to be displayed tothe human user via the eye-mounted display. The femtoprojectors 210project the images on the user's retina, thus creating an image ofvirtual objects in the user's field of view. The scaler receives theinput images and produces the appropriate data and commands to drive thefemtoprojectors. The head tracker and eye tracker provide informationabout head movement/position and eye movement/position, so that theinformation provided to the femtoprojectors can be compensated for thesefactors.

There are many ways in which this functionality can be configured withan eye-mounted display(s) to create embodiments of eye-mounted displaysystems. Portions of these subsystems may be external to the user, whileother portions may be worn by the user in the form of a headpiece orglasses. Components may also be worn on a belt, armband, wrist piece,necklace, or other types of packs. FIG. 1A shows an example where somefunctionality is implemented in a necklace 160 worn by the user.

The scleral contact lenses 110 can take various shapes, not justcircular and oval. FIG. 3 shows another eye-mounted display mounted onthe user's eye, where the perimeter 312 of the contact lens 110 has anirregular shape. The contact lens also contains a set offemtoprojector(s) 120, various other components 140, and a conductivecoil 345. In the drawing, the coil 345 follows the outline of theperimeter 312, but it is not required to do so. For example, it may bemore rounded to reduce corners in the conductive coil 345.

FIGS. 4A and 4B show the perimeters 412 of the contact lenses 110 ofFIGS. 1B and 3, respectively. The dashed line shows an inscribed circle.The sizes of the contact lenses 110 can be described by their width “w”and height “h.” The height and width are equal for a circular contactlens. As seen in FIGS. 4A and 4B the width can be larger than theheight. In the examples shown, w=24 mm and h=16 mm, for a w/h ratio=1.5.In some embodiments, the width w is between 10 mm and 30 mm and,similarly, the height h is between 10 mm and 30 mm. For example, theheight h of the contact lens is at least 11 mm. In another example, thewidth of the contact lens is at least 20 mm. In some embodiments, theperimeter 412 of the non-circular contact lens 100 has an enclosed areabetween 80 mm² and 800 mm². In some embodiments, the shape of theperimeter 412 depends on available eye contour information.

In both FIGS. 4A and 4B, a conductive coil that follows the non-circularperimeter 412 of the contact lens 110 will enclose a larger area than acircular conductive coil that would also fit within the contact lens110. This larger area compared to a circular contact lens can result inmore power transferred to the conductive coil, because voltage isproportional to the area and power is proportional to the square of thevoltage. For example, consider FIG. 4A. Assume the coil is 1 mm awayfrom the perimeter. For a circular contact lens with a diameter of 16mm, the conductive coil will have a diameter of 14 mm and an area of 154mm². The conductive coil for the elliptical contact lens in FIG. 4A hasmajor and minor axes of 22 mm and 14 mm, respectively. The enclosed areais 242 mm², or about 60% greater induced voltage and about 150% morepower than the circular contact lens.

A non-circular scleral contact lens 110 with an increased footprint canalso be designed to include larger interior spaces for payloads (such aspayload space 230 in FIG. 2A), compared to a conventional circularcontact lens. As a result, larger payloads or more payloads may becontained in the contact lens. In some designs, the payload space has athickness of 1 mm or more (e.g., a thickness of at least 0.2 mm over anarea of at least 10 mm²). Alternately, the payload space can have avolume of 300 mm³ or more (e.g., a volume of at least 1 mm³).

Generally, the more scleral area that a lens covers and/or matches, thegreater the lens stability and user comfort. Thus, in someimplementations, non-circular contact lenses 110 are customized toincrease the contact area with and/or to better fit the contour of auser's eye 120. As such, the contact lens 110 may be aspheric andasymmetric. In some cases, a contact lens 110 is customized to increasethe contact area with the user's sclera, for example by better matchingthe shape of the user's eye opening. In other cases, a contact lens 110is customized to better match the interior surface of the contact lensto the contour of the eye. The interior surface of the contact lens 110can be designed to grip the outside surface of the eye. Theseembodiments can further reduce contact lens 110 movement and rotation,resulting in increased positional stability of the contact lens andprojected image relative to the eye.

To obtain a customized contact lens 100, the contour of a user's eye maybe measured. Techniques that measure the contour of the sclera may beadvantageous because the contour information of the sclera (e.g., thearea adjacent to the cornea) may be used to generate a well-fittinglens. For example, to enhance stability, the contact area between thecontact lens and sclera may be at least 3 mm wide. Therefore, to designa customized contact lens, careful measurements of the sclera, andpossibly a combination of multiple measurements of the sclera, may beused to construct a three-dimensional contour of the eye.

The contour of a user's eye can be measured using direct molding or byusing structured light scanning, among other techniques. In directmolding, a mold of the user's eye contour is created by impressing themold material directly onto the user's eye. The mold captures thecontour of the eye and can be digitized (e.g., by scanning) to capturethe relevant three-dimensional information. In structured lightscanning, patterned light is projected onto the user's eye. The contourof the eye causes variations in the light pattern. These variations canbe captured and then used to reconstruct a three-dimensional contour ofthe eye.

The contact lenses 110 themselves can be shaped using a diamond lathe.The lathe can be equipped with multiple axes that are synchronized tospindle rotation in order to cut a customized asymmetric lens shape. Forexample, the lathe is a two axis continuous path contouring and edginglathe that directly machines the contact lenses.

The lens design can be carried out by a trained professional using theavailable three-dimensional eye contour information (e.g., from directmolding, structured light scanning or other types of opticaltopography). The lens shape can be non-circular and can be determinedbased on the available eye contour information. The interior surface ofthe contact lens can be shaped to fit the contour of the eye. In somecases, optical information relevant to the optical zone of the contactlens can be entered based on the user's needs (e.g., vision correctioninformation). The final lens design can be generated based on thisinformation and it can be reviewed by a trained professional before lensfabrication.

Although the detailed description contains many specifics, these shouldnot be construed as limiting the scope of the invention but merely asillustrating different examples. It should be appreciated that the scopeof the disclosure includes other embodiments not discussed in detailabove. Various other modifications, changes and variations which will beapparent to those skilled in the art may be made in the arrangement,operation, and details of the method and apparatus disclosed hereinwithout departing from the spirit and scope as defined in the appendedclaims. Therefore, the scope of the invention should be determined bythe appended claims and their legal equivalents.

What is claimed is:
 1. An eye-mounted display comprising: a scleralcontact lens that rests on a sclera of a user's eye, the scleral contactlens having a non-circular perimeter; and a femtoprojector mounted inthe contact lens, the femtoprojector projecting images onto a retina ofthe user's eye when the contact lens is mounted on the user's eye. 2.The eye-mounted display of claim 1 further comprising: a conductive coilcontained in the contact lens, the conductive coil wirelessly receivingpower to power the eye-mounted display.
 3. The eye-mounted display ofclaim 2 where the conductive coil has a same shape as the non-circularperimeter of the contact lens.
 4. The eye-mounted display of claim 2where the conductive coil lies within 2 mm of the non-circular perimeterof the contact lens.
 5. The eye-mounted display of claim 2 where theconductive coil has a larger area than a circular conductive coil thatwould also fit within the contact lens.
 6. The eye-mounted display ofclaim 1 where a width of the contact lens is larger than a height of thecontact lens.
 7. The eye-mounted display of claim 6 where thenon-circular perimeter of the contact lens has an oval shape.
 8. Theeye-mounted display of claim 6 where the non-circular perimeter of thecontact lens has an irregular shape.
 9. The eye-mounted display of claim1 where the contact lens extends beneath an eyelid of the user's eyewhen the user is wearing the contact lens, and a width of the contactlens is larger than a height of the contact lens.
 10. The eye-mounteddisplay of claim 1 where a width of the contact lens is at least 20 mm.11. The eye-mounted display of claim 1 where the non-circular perimeterencloses an area of at least 80 mm².
 12. The eye-mounted display ofclaim 1 where the contact lens contains an interior space outside anoptical zone of the contact lens, the interior space containing apayload for the eye-mounted display.
 13. The eye-mounted display ofclaim 12 where the interior space has a thickness of at least 0.2 mmover an area of at least 10 mm² or has a volume of at least 1 mm³. 14.The eye-mounted display of claim 1 where a portion of the contact lensin front of the sclera has an appearance that matches a coloring of thesclera.
 15. The eye-mounted display of claim 1 further comprising apayload mounted in a portion of the contact lens in front of the sclera,where the portion of the contact lens in front of the sclera has anappearance that matches a coloring of the sclera and obscures thepayload.
 16. The eye-mounted display of claim 1 where a shape of thenon-circular perimeter is customized to the user's eye.
 17. Theeye-mounted display of claim 1 where an interior surface of the contactlens is customized to a contour of the user's eyeball.
 18. Theeye-mounted display of claim 17 where the contour of the user's eyeballis measured by direct molding or structured light scanning, and theinterior surface of the contact lens is customized based on the measuredcontour.
 19. The eye-mounted display of claim 17 where the contact lensis manufactured into a customized aspheric shape using a multi-axislathe.
 20. The eye-mounted display of claim 1 where the contact lensmakes contact with the sclera over a contact area that is at least 3 mmwide.